The present invention relates to an improvement in the transfer of particulate material from a photoreceptor element and the development and cleaning thereof, and in particular to a photoreceptor element comprising a piezoelectric component in an electrostatographic imaging device.
An example of an electrostatographic imaging device known in the art is described in U.S. Pat. No. 4,766,457 to Barker et al., assigned to the same assignee as the present application and is incorporated herein by reference. In such a device, developing powder, or toner, is transferred from a toner carrier to an electrostatographic image on a photoreceptor component. This developed image can then be transferred to paper or other printing material to form a more permanent representation of the electrostatographic image. Subsequently, the photoreceptor component is cleaned and the process can then be repeated.
In previous electrostatographic imaging devices, improved transfer from the toner carrier to the photoreceptor and from the photoreceptor to paper is achieved by agitating either the toner carrier or the photoreceptor. This agitation promotes the release of toner particles to the desired areas of development in the receptor.
As seen in U.S. Pat. No. 4,833,503, the development apparatus of a copying machine comprises a donor belt made of a piezoelectric polymer material. An external A.C. source supplies voltage to the belt through one of the rollers of the development apparatus. The net force of adhesion of toner to the belt is reduced through agitation of the piezoelectric belt surface. Therefore, an improved development of the final copy or print is achieved by the removal of more toner from the donor belt.
In U.S. Pat. No. 4,546,722, several methods for the removal of toner particles from the toner carrier are shown. In one method, a piezoelectric element is disposed in the carrier. An external A.C. source causes this piezoelectric element to vibrate, thus aiding in the release of toner from the carrier. In another method, the toner carrier is formed as a sheet having a piezoelectric layer. The carrier sheet is then securely clamped, and an A.C. source causes the entire sheet to vibrate having the results as mentioned above.
In U.S. Pat. No. 3,140,199, an external vibration mechanism is used to agitate the carrier belt. In U.S. Pat. No. 4,111,546, an external vibration mechanism is used to agitate the photoreceptor to remove toner residue. These vibration mechanisms can be acoustic or ultra-acoustic devices such as horns.
In U.S. Pat. No. 3,653,758, piezoelectric devices are coupled to the photoreceptor. If the photoreceptor is a plate, these piezoelectric devices can be disposed in a support structure for the photoreceptor. If the photoreceptor is a belt, these vibration devices can be placed in any of the rollers, around which the photoreceptor belt is moved.
In the previous methods mentioned above, external vibration devices or support structures agitate the photoreceptor or toner carrier. Space is provided in the copying system in order to incorporate these devices and support structures in the system. As the complexity of these copying systems increases, it becomes more difficult to provide space for these devices and support structures.
The systems described above under utilize space and lack cost efficiencies because of the need for external devices and support structures.
Furthermore, the quality of copy using such systems could be improved by transferring more toner during each stage of the copying process.